Orgasm PLEASE!!!

I know that many women can't have orgasms through penetration. And after 6 years of having sex I have still never been able to have an orgasm from penetration, self United clitoral stimulation only. It kind of sucks.  I now am in a long term relationship and men being the self conscious beings that they are he's convinced that he sucks in bed because he can't make me cum. And though I've tried to assure him that I simply can't orgasm from penetration alone heals still kind of down about. Guys any tips or tricks you all may know that could help out would be awesome. I understand that a great deal about sex is about learning what works best for your body but I've been experimenting for years and no amount of reading Cosmo has helped.